Güralp DM24 MkIII Operator's Manual
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Güralp DM24 MkIII Operator's Manual

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Güralp DM24 MkⅢ
Operator's Guide
Document Number: MAN-D24-0004
Issue U – December, 2021
Designed and manufactured by
Güralp Systems Limited
3 Midas House, Calleva Park
Aldermaston RG7 8EA
England

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  • Page 1 Güralp DM24 MkⅢ Operator’s Guide Document Number: MAN-D24-0004 Issue U – December, 2021 Designed and manufactured by Güralp Systems Limited 3 Midas House, Calleva Park Aldermaston RG7 8EA England...

  • Page 2: Table Of Contents

    Güralp DM24 MkⅢ Contents Table of Contents 1 Preliminary Notes......................8 1.1 Proprietary Notice.......................8 1.2 Cautions and Notes....................8 1.3 Manuals and Software....................8 1.4 Conventions........................8 2 Introduction........................9 2.1 Features........................10 3 Installing the DM24......................12 3.1 Power supplies......................12 3.2 Connecting sensors....................12 3.3 Connecting external hardware.................13 3.3.1 FireWire disks....................13 3.4 The DM24BH borehole digitiser................15 4 Using the DM24......................16...
  • Page 3 Güralp DM24 MkⅢ 4.5 Downloading stored data..................25 4.5.1 Downloading over FireWire................26 4.5.2 Reading DM24 disks..................26 4.5.3 Downloading over the serial link...............29 4.6 DM24 USB Host Operations..................31 4.6.1 DM24 Mk3 USB host option................31 4.6.2 Formatting a USB device..................32 4.6.3 Directory structure.....................32 4.6.4 System operation....................33 5 Using Scream!........................35 5.1 Configuring digitisers....................35...
  • Page 4 Güralp DM24 MkⅢ 6.4.3 SET-CLOCK......................61 6.4.4 TIME?........................62 6.4.5 getWNROpivot....................62 6.4.6 setWNROpivot....................62 6.4.7 LEAPSECOND....................62 6.4.8 SQPATCH......................63 6.5 Port configuration.....................63 6.5.1 BAUD.........................63 6.5.2 STOPBITS......................64 6.5.3 +MODEM......................64 6.5.4 –MODEM......................65 6.5.5 +GCFIN......................65 6.5.6 –GCFIN......................66 6.5.7 OPEN........................66 6.5.8 USBPORT......................66 6.6 Output configuration....................67 6.6.1 SAMPLES/SEC....................67 6.6.2 CONTINUOUS....................67 6.6.3 SET-TAPS......................68 6.6.4 COMPRESSION....................68 6.6.5 LOWLATENCY....................69...
  • Page 5 Güralp DM24 MkⅢ 6.9.7 AUTOCAL?......................79 6.9.8 -AUTOCAL......................80 6.10 Actions........................80 6.10.1 LOCK.......................80 6.10.2 UNLOCK......................80 6.10.3 CENTRE......................80 6.10.4 MASSES?.......................81 6.10.5 %AUTO-CENTRE...................81 6.10.6 O/SNULL......................81 6.10.7 RE-SYNC......................81 6.10.8 ?LITHIUM......................82 6.10.9 RE-BOOT......................82 6.11 Data storage and transmission................82 6.11.1 SHOW-FLASH....................82 6.11.2 RESET-FLASH....................83 6.11.3 ERASEFILE.....................83 6.11.4 EVENTSLIST....................84 6.11.5 RESET-LIST....................84 6.11.6 DIRECT......................85 6.11.7 FILING......................85...
  • Page 6 Güralp DM24 MkⅢ 7 Inside the DM24......................95 7.1 State of health information..................95 7.1.1 Heartbeat messages..................95 7.1.2 Status blocks in continuous mode..............97 7.2 GPS and Synchronisation..................99 7.2.1 Overview......................99 7.2.2 Leap-seconds....................100 7.2.3 Week-number roll-over..................100 7.2.4 Multiple re-synchronisation events..............101 7.3 Updating firmware....................103 7.3.1 Updating firmware using an EAM, Affinity or NAM.........103 7.3.2 Updating firmware with Scream!..............103 7.4 Setting up external triggering.................106 7.4.1 Overview......................107...
  • Page 7 Güralp DM24 MkⅢ 10 Digitiser specifications.....................128 11 Revision history......................130 MAN-D24-0004 Issue U - December, 2021...

  • Page 8: Preliminary Notes

    Güralp DM24 MkⅢ Preliminary Notes 1 Preliminary Notes 1.1 Proprietary Notice The information in this document is proprietary to Güralp Systems Limited and may be copied or distributed for educational and academic purposes but may not be used commercially without permission.

  • Page 9: Introduction

    Güralp DM24 MkⅢ Introduction 2 Introduction The Güralp DM24 multi-channel digitiser is a state-of-the-art digital module for seismic data. It can be supplied in several different formats: A stand-alone DM24 can be installed with existing or new analogue sensors. Conversely, a modular digitiser is fixed to, and becomes a physical part of, a Güralp seismometer.

  • Page 10: Features

    Güralp DM24 MkⅢ Introduction For these units, the main interface to the DM24 is via the EAM's web and command line. The manual MAN-EAM-0003, available from the Güralp web site, is more appropriate for these units than is this document. The DM24 can also be supplied in borehole sonde form, with optional strain relief accessories.
  • Page 11 Güralp DM24 MkⅢ Introduction Time synchronization to an attached GPS receiver. • An ARM microprocessor, which formats and buffers data in an on-board • 256 kByte RAM ring-buffer. Efficient data storage and transmission using the Güralp Compressed Format • (GCF). RS232-compatible serial data output at user-selectable baud rates, with •...

  • Page 12: Installing The Dm24

    Güralp DM24 MkⅢ Installing the DM24 3 Installing the DM24 3.1 Power supplies The DM24 accepts power from lines in its DATA OUT port. This uses a Güralp standard ten-pin combined serial/power interface, a cable for which can be obtained from Güralp Systems, part number CAB-BDA-0036.

  • Page 13: Connecting External Hardware

    Güralp DM24 MkⅢ Installing the DM24 3.3 Connecting external hardware On a stand-alone DM24, the digital ports are located on the opposite side to the analogue ports: The DM24 transmits data through its DATA OUT port. This is an RS232-compatible serial link, outputting data in GCF format according to the particular configuration of the instrument.
  • Page 14 Güralp DM24 MkⅢ Installing the DM24 Before you can use the disk, you will need to reset it. The DM24 saves data on the hard disk in a special format, DFD, so you cannot use your PC's operating system tools to reset the disk. You can use the DM24 itself, Scream!, or GCFXtract software to reset the disk.

  • Page 15: The Dm24Bh Borehole Digitiser

    Güralp DM24 MkⅢ Installing the DM24 6. Key to reset the disk. 7. When the reset is complete, remove the disk. You will now be able to download data onto the disk when required. 3.4 The DM24BH borehole digitiser When the DM24 is ordered in borehole form, it is supplied with a surface interface unit for installation at the top of the borehole.

  • Page 16: Using The Dm24

    Güralp DM24 MkⅢ Using the DM24 4 Using the DM24 Once the DM24 is connected to your equipment, it will start producing data immediately. You can now start configuring it for your own needs. There are two ways you can do this: using the graphical interface provided by Scream!, or •...

  • Page 17: Triggering

    Güralp DM24 MkⅢ Using the DM24 4.1.1 Triggering The DM24 has a flexible triggering system. When the digitiser triggers, it can optionally output (or store – see DUAL mode in section 4.3 on page 22) additional data. Any combination of tap and component can be output as the result of a trigger. In the example above, you might configure the sensor to output Tap 2 data (at 10 samples/s) continuously, but when a trigger is declared, to output Tap 0 data (at 500 samples/s) as well.

  • Page 18: Digitisers For Multiple Instruments

    Güralp DM24 MkⅢ Using the DM24 Z, N, and E denote the vertical, north/south, and east/west components • respectively. X denotes the fourth full-rate data channel, which is provided for connection • to your own monitoring equipment via the AUXILIARY connector (if present). C denotes the calibration input channel, which replaces the X stream whilst •...

  • Page 19: Transmission Modes

    Güralp DM24 MkⅢ Using the DM24 A 6-channel digitiser will output full-rate streams with the following final characters: Z/N/E0 SENSOR A at tap 0 Z/N/E1 SENSOR B at tap 0 Z/N/E2 SENSOR A at tap 1 Z/N/E3 SENSOR B at tap 1 Z/N/E4 SENSOR A at tap 2 Z/N/E5 SENSOR B at tap 2 Z/N/E6 SENSOR A at tap 3...

  • Page 20: Direct

    Güralp DM24 MkⅢ Using the DM24 4.3.1 DIRECT Command: DIRECT Instructs the DM24 not to use Flash memory for storage. Instead, all data are transmitted directly to clients. An instrument in DIRECT mode still honours the GCF Block Recovery Protocol: a temporary RAM buffer always holds the last 256 blocks generated and, if a client fails to receive a block, it can request its retransmission.

  • Page 21: Duplicate

    Güralp DM24 MkⅢ Using the DM24 Instructs the DM24 not to transmit blocks to clients automatically, but to store all digitized data in the Flash memory. If you have chosen the RECYCLE buffering mode (see below), the memory is used in circular fashion, i.e. if it becomes full, incoming blocks begin overwriting the oldest in memory.

  • Page 22: Dual

    Güralp DM24 MkⅢ Using the DM24 4.3.4 DUAL Command: DUAL Instructs the DM24 to transmit any continuous streams directly to clients as for DIRECT mode, but to store triggered data into Flash storage as in FILING mode. If you choose DUAL mode but do not select any continuous streams for output, the instrument will send heartbeat messages as in FILING mode.
  • Page 23 Güralp DM24 MkⅢ Using the DM24 transmitted in real-time where possible, but are worried about possible breaks in communication, you should use ADAPTIVE mode instead. FIFO mode will consider a data block successfully transmitted once it has received an acknowledgement from the next device in the chain. If there are several devices between you and the instrument, you will need to set up the mode for each device (if applicable) to ensure that data flow works the way you expect.

  • Page 24: Transmission Mode Summary

    Güralp DM24 MkⅢ Using the DM24 4.3.6 Transmission mode summary Transmission Mode: Function Transmit continuous data: ✘ ✔ ✔ ✔ ✔ ✔ Store continuous data: ✘ ✔ ✔ ✘ ✔ Transmit trigger data: ✔ ✘ ✔ ✘ ✔ ✔ Store trigger data: ✘...

  • Page 25: Write-Once

    Güralp DM24 MkⅢ Using the DM24 For example, in DUAL mode with RECYCLE buffering, the latest continuous data will be transmitted to you as normal, and the latest triggered data may be retrieved from the Flash memory using Scream! or the command line. However, if you do not download data regularly from the Flash memory, you may lose older blocks.

  • Page 26: Downloading Over Firewire

    Güralp DM24 MkⅢ Using the DM24 4.5.1 Downloading over FireWire To download data over FireWire, plug the disk in and issue the command DISKMENU from the digitiser's console. The digitiser will reply with a list of download options. If you have not used the disk before, you will need to reset it. Resetting the disk prepares it for the DM24 to use and sets up the DFD filing system (see below).
  • Page 27 Güralp DM24 MkⅢ Using the DM24 To read a disk using GCFXtract: Attach the disk to your computer. You can use FireWire, USB, or any other interface supported by your computer and the disk. 2. Run GCFXtract and select the required disk from the drop-down list, then click GCFXtract will scan the disk and display all the streams it finds in the selection area below.
  • Page 28 Güralp DM24 MkⅢ Using the DM24 7. Normally, GCFXtract outputs GCF files, to ensure all the information in the original data is retained. If you want to convert to a different format, select it from the Output Data Format drop-down box. GCFXtract can output in most of the formats supported by Scream!.

  • Page 29: Downloading Over The Serial Link

    Güralp DM24 MkⅢ Using the DM24 6. Select the streams you want to replay, and click Open. The disk will appear in the left-hand pane of Scream!'s main window, and the streams you have selected will start playing into the stream buffer, as well as being recorded. 7.
  • Page 30 Güralp DM24 MkⅢ Using the DM24 If you wish to download only a subset of data, you can replace the ALL-FLASH and ALL-DATA modifiers with other modifiers to select different streams and/or time periods: The streams to be downloaded are specified with ALL-DATA, S/S, or STATUS- •...

  • Page 31: Dm24 Usb Host Operations

    Güralp DM24 MkⅢ Using the DM24 4.6 DM24 USB Host Operations DM24s can be supplied with an optional USB interface. This section describes the use of this interface. 4.6.1 DM24 Mk3 USB host option This interface enables the DM24 to record GCF data to a standard USB disk drive or Flash memory stick using the ISO 9293 FAT filing format –...

  • Page 32: Formatting A Usb Device

    Güralp DM24 MkⅢ Using the DM24 page 19. As no contiguous streams are sent via the serial port in these modes, nothing will be written to the USB device. To record data to a USB device, the system should be configured in DIRECT or DUPLICATE mode –...

  • Page 33: System Operation

    Güralp DM24 MkⅢ Using the DM24 SLOW is the size, in hours, for lower sample rates < SPS STATUS is the size, in hours, for status stream files. The default settings are: 1 40 4 12 HOURFILES With these settings, the system will start a new file every hour for streams with a ≥...
  • Page 34 Güralp DM24 MkⅢ Using the DM24 When the operation has been completed, the system reports the available space using the optional LCD and, also, in the status stream, as in the example below: 2008 10 3 13:18:49 USB Flash stick Recording started NO NAME D:/>...

  • Page 35: Using Scream

    Güralp DM24 MkⅢ Using Scream! 5 Using Scream! Scream! is a versatile seismic data visualisation program for Güralp instruments which runs on Windows and Linux computers. If a DM24's DATA OUT port is connected to an RS232 port on a computer running Scream!, the program can be used to analyze digitized data from the DM24's connected analogue sensors, and to control/configure both the digitiser and the sensors themselves.

  • Page 36: System Id

    Güralp DM24 MkⅢ Using Scream! calibration signal options; and • mass control functions. • Some of these options can also be altered in the Configuration setup window. For more information on the Control window, see Section 5.2 on page 50. If you need a more powerful interface to the DM24, you can also issue commands to it directly using Scream!'s terminal mode.

  • Page 37: Output Control

    Güralp DM24 MkⅢ Using Scream! institution’s name, etc. The system identifier can be up to 5 characters long, whilst the serial number cannot be longer than 4. Sensor Type : If the sensor attached to the digitiser is a Güralp velocity sensor, useful seismometer functions (such as sensor locking, centring, and calibration) may be controlled through the digitiser.
  • Page 38 In the example above, all three axes are being output at Tap 2 (20Hz). The DM24 MkIII has a fourth channel for external input and calibration, which can also be output at any tap.
  • Page 39 Güralp DM24 MkⅢ Using Scream! In the example above, we might want the high-rate data from Tap 0 to be generated only when an event registers. To do this, the lower check-boxes of Tap 0 should be ticked: With this configuration uploaded, Tap 2 will continue to produce output at all times, but Tap 0 will also emit data whenever the trigger criteria are met.

  • Page 40: Triggering

    Güralp DM24 MkⅢ Using Scream! Scream’s main window might then appear as below: In this example: DA79 is the serial number of the digitiser. • Stream Ids ending Z0, N0 and E0 correspond to input channels Z, N, and • E, with output derived from Tap 0.

  • Page 41: Sta/Lta - Triggering By Average Values

    Güralp DM24 MkⅢ Using Scream! tap. Scream! 4.5 also allows you to configure each digitiser to receive triggers from other digitisers. To create a new stream with a trigger, open Scream!'s Digitiser configuration window for the relevant digitiser, and click on the Output control tab. In the Output control pane, a tap which gives rise to a triggered stream has a tick in the lower row of its grid of check-boxes.
  • Page 42 Güralp DM24 MkⅢ Using Scream! You can select which tap is tested for the trigger from the Data source drop-down menu. The tap does not have to output data to Scream! for you to be able to use it here. Any or all of the channels available at that tap may be used to determine a trigger.
  • Page 43 Güralp DM24 MkⅢ Using Scream! For example, setting the STA to 1 second, the LTA to 10 seconds and the Ratio to 4 would give rise to the following trigger behaviour: Usually, the values of the STA and LTA periods, and of the Ratio, will be the same for all checked channels.
  • Page 44 Güralp DM24 MkⅢ Using Scream! Since it is not generally advisable to trigger from broadband data, the digitiser provides a set of standard bandpass filters to apply to the data streams before they are tested for the trigger condition. This filtering serves to maximise sensitivity within the frequency band of interest, and filter out noise outside this band.
  • Page 45 Güralp DM24 MkⅢ Using Scream! MAN-D24-0004 Issue U - December, 2021...

  • Page 46: Level Triggering

    Güralp DM24 MkⅢ Using Scream! 5.1.5 Level triggering Using the Level triggering method, a trigger is generated whenever one of the checked components reaches a certain level above the baseline. You can select which tap is monitored from the Data source drop-down menu, and the channel(s) to be considered from the Channel column of the table.

  • Page 47: Pre-Trigger And Post-Trigger Recording

    Güralp DM24 MkⅢ Using Scream! 5.1.7 Pre-trigger and post-trigger recording In order to capture all of a seismic event, it is often useful to be able to record data immediately preceding the trigger. Güralp digitisers have an internal buffer of some seconds which allows these data to be added to the triggered stream.
  • Page 48 Güralp DM24 MkⅢ Using Scream! If a tick is placed in the box next to a channel, its data will be collected and transmitted as a data stream in GCF format, just as with the normal data channels. To indicate that the data come from a Mux channel, the Stream ID will take the form ****Mx, where M stands for Mux and x is a hexadecimal integer ( i.e.

  • Page 49: Ports

    Güralp DM24 MkⅢ Using Scream! 5.1.9 Ports The Baud Rates pane of the Configuration setup window allows you to program the baud rate and stop bits for the DM24's output port. The baud rate you choose must satisfy two conditions: It must be high enough to allow all the transmission of all data generated by •...

  • Page 50: Controlling Digitisers

    Güralp DM24 MkⅢ Using Scream! selecting Configure… from the pop-up menu: for more details, consult the online help or user guide for Scream!. If you are using an additional communications device, you should consult its documentation to learn how to set its baud rate. 5.2 Controlling digitisers To control a digitiser whilst it is running, either right-click on the digitiser's icon in the list to the left of Scream!'s main window ( ) and click Control…, or simply...

  • Page 51: Triggering

    Güralp DM24 MkⅢ Using Scream! If you change the Sensor Type, you will have to click , close the Control window, and open a new one before you can access the Mass Control options. Enable GPS power cycling: If you are using a GPS unit to receive time signals, but do not experience significant drift in the system's clock (for example, in a stable- temperature environment), you can save power by selecting Enable GPS power cycling.

  • Page 52: Calibration

    Güralp DM24 MkⅢ Using Scream! 5.2.3 Calibration You can check that your instrumentation is correctly calibrated by injecting known signals into the sensor's feedback loop. The Calibration pane allows you to do this once the sensors are installed. Each channel Z, N/S and E/W can be calibrated separately. For most triaxial digital instruments, each channel calibrates the corresponding axis of the instrument;...

  • Page 53: Mass Control

    Güralp DM24 MkⅢ Using Scream! rate to 4 (Hz). In this manner, you can select frequencies ranging from 0.1 to 10 Hz (10 to 0.1 s periods). You can specify step calibration by selecting the Square wave button. The square wave consists of a positive step at the start of the next minute of the digitiser’s internal clock, followed by a negative step after a specified number of minutes.

  • Page 54: Data Flow

    Güralp DM24 MkⅢ Using Scream! from Scream, but must be locked and unlocked manually, whilst a 3T has remote lock and unlock commands. Conversely, Güralp 5T strong-motion instruments must be centred manually, and do not need locking or unlocking. If you have set the Sensor Type to CMG-5T or CMG-5TD, the Mass Control tab will not be available.
  • Page 55 Güralp DM24 MkⅢ Using Scream! stop writing and switch the DM24 into DIRECT mode. • Clicking in this window immediately activates the transmission mode you have selected—there is no need to reboot. If you prefer, you can use the DM24 command line to switch between transmission modes, as described in section 6.11 on page 82.

  • Page 56: Command Line Interface

    Güralp DM24 MkⅢ Command line interface 6 Command line interface 6.1 Introduction You can connect to the internal software of the DM24 over its output serial port and communicate with it. To enter command mode from Scream!, right-click on the digitiser's icon ( ) and select Terminal…...

  • Page 57: Getting Help

    Güralp DM24 MkⅢ Command line interface thing you typed), they will execute, remove themselves from the stack, and then remove further items from the stack to use as arguments. Thus, in the command 3 SENSOR-TYPE the 3 has no immediate effect, so stays on the stack; SENSOR-TYPE takes itself and the previous item (here 3) off the stack, then performs its action on the 3 (here, setting the configured sensor type to 3, representing a Güralp 3T sensor).

  • Page 58: Explain

    Güralp DM24 MkⅢ Command line interface When you have finished using the extended dictionary, close it with the command [seal] (including the square brackets), so you do not inadvertently change the internal settings with subsequent commands. Alternatively , the command may not be implemented in the firmware version •...

  • Page 59: Serial2

    Güralp DM24 MkⅢ Command line interface 6.3.2 SERIAL2 Syntax: SERIAL2 (interactive) Sets the serial number for a second sensor (for seven-channel digitisers) to a value you supply. SERIAL2 Secondary Serial # {0} ? 6 characters : C903,00 The serial number you supply must contain exactly four alphanumeric (0-9A-Z) characters followed by a comma and two zeros (which are ignored - see the discussion of serial numbers at SET-ID, above).

  • Page 60: Cross

    Güralp DM24 MkⅢ Command line interface angle is the measured angle of deviation from the North/South axis, in tenths of a degree. The angle of deviation is the negative of the angle by which you want incoming signals to be rotated. Like all other parameters, it must be an integer ( i.e. a whole number of tenths of a degree).

  • Page 61: Cycle

    Güralp DM24 MkⅢ Command line interface 6.4.2 HR-CYCLE Syntax: interval HR-CYCLE Sets the time to wait between GPS synchronizations. To save power, the DM24 can switch off the attached GPS receiver once its internal precision clock has been successfully synchronized. The GPS receiver is reactivated every interval hours to ensure that the clock remains correct, and shut down again once the clock error has stabilized.

  • Page 62: Time

    Güralp DM24 MkⅢ Command line interface 6.4.4 TIME? Syntax: TIME? Displays the current date and time from the software clock that is used to time- stamp digitised data. See SET-CLOCK for more details. 6.4.5 getWNROpivot Syntax: getWNROpivot Prints the configured GPS week-number roll-over pivot date. See setWNROpivot, below, for more details.

  • Page 63: Sqpatch

    Güralp DM24 MkⅢ Command line interface system may, for example, be configured for GPS power-cycling and the receiver may be powered down - the digitiser will produce data with incorrect time-stamps until it can resynchronise to the GPS receiver again. If the digitiser is notified in advance about an upcoming leap-second, this situation can be avoided and the leap-second will be handled correctly even if GPS data are unavailable at the time.

  • Page 64: Stopbits

    Güralp DM24 MkⅢ Command line interface For example, 0 38400 BAUD 1 4800 BAUD 2 38400 BAUD This will reset a standard single-sensor DM24 to its default configuration. The allowable values for baud-rate are 4800, 7200, 9600, 14400, 19200, 38400, 57600, 115200 and 230400.

  • Page 65: Modem

    Güralp DM24 MkⅢ Command line interface If you have already configured a telephone number, the command will print out the current setting and ask if you want to change it. +MODEM Phone# 00441189819056 New number? y/n y Enter phone# 00441189819943 Phone# 00441189819943 Flash FIFO : Circular Configuration for dial out...

  • Page 66: Gcfin

    Güralp DM24 MkⅢ Command line interface 6.5.6 –GCFIN Syntax: input-port -GCFIN Instructs the digitiser to stop accepting GCF input on input-port, and to return the port to normal operation. 6.5.7 OPEN Syntax: OPEN system-id stream-id-prefix (n.b.) Opens a terminal session to a second, connected digitiser. The DM24 scans all the ports which are currently accepting GCF input (see +GCFIN, above) to find a digitiser which matches system-id and stream-id-prefix.

  • Page 67: Output Configuration

    Güralp DM24 MkⅢ Command line interface 6.6 Output configuration 6.6.1 SAMPLES/SEC Syntax: tap-0 tap-1 tap-2 tap-3 samples/sec The DSP software on the DM24 supports up to 7 cascaded filter/decimation stages. At each stage, the sample rate can be divided by a factor of 2, 4 or 5. The internal ADC outputs data at 2000 samples per second, so decimated data streams are available from 1,000, 500 and 400 samples/sec down to 1 sample/sec.

  • Page 68: Set-Taps

    Güralp DM24 MkⅢ Command line interface Thus, for example: 0 1 CONTINUOUS will output the Z component only (1) at the first tap; • 0 2 CONTINUOUS will output the N component only (2); • 0 4 CONTINUOUS will output the E component only (4); •...

  • Page 69: Lowlatency

    Güralp DM24 MkⅢ Command line interface The digitiser compresses data without loss, so compression is most effective when the data contain relatively little information. During large or local seismic events, the digitiser normally needs to decrease the compression level. bits can be one of 8BIT, 16BIT and 32BIT. 8BIT (the default) is the maximum amount of compression;...

  • Page 70: Setdss

    Güralp DM24 MkⅢ Command line interface Note: When LOWLATENCY is active, the TRIGGERS and BANDPASS commands have special meanings. Because of this, the STA/LTA triggering function is disabled. You can still use LEVEL triggering if you require (see below). 6.6.6 SETDSS Syntax: output-spec SETDSS This command alters the way the DM24 outputs its status streams.

  • Page 71: Variable Gain

    Güralp DM24 MkⅢ Command line interface The bits should be logically ORed ( i.e. the decimal numbers added) to produce multiple status lines. For example, the command 6 SETDSS (6 = bit 2 OR bit 4) will cause the digitiser to begin outputting status blocks containing GPS timing and position information only: 2006 4 13:13:00 o/s=...

  • Page 72: Triggering

    Güralp DM24 MkⅢ Command line interface parameter can also be one of 4 (vertical), 5 (North/South) or 6 (East/West), referring to the components from the second instrument. gain specifies the gain and is one of 1, 2, 4, 8, 16, 32 or 64. The digitiser must be rebooted before this change will take effect.

  • Page 73: Sta

    Güralp DM24 MkⅢ Command line interface tap is the tap number at which to output the triggered stream. You can set which taps output which sample rate using the SAMPLES/SEC command, described above. components is an integer below 16, which represents which components to output in the same fashion as in the CONTINUOUS command, above.

  • Page 74: Ratios

    Güralp DM24 MkⅢ Command line interface 6.8.7 RATIOS Syntax: Z-ratio N-ratio E-ratio X-ratio RATIOS Sets the ratio of STA to LTA above which a trigger will be declared in the STA/LTA triggering algorithm. Z-ratio, N-ratio, E-ratio and X-ratio are the threshold ratios for the Z , N , E , and auxiliary components respectively.

  • Page 75: Microg

    Güralp DM24 MkⅢ Command line interface filter = 2 creates a filter with a corner at 20 % of the Nyquist frequency for • tap tap ( i.e. 15 % of its sample rate); and filter = 5 creates a filter with a corner at 50 % of the Nyquist frequency for •...

  • Page 76: Triggerin

    Güralp DM24 MkⅢ Command line interface 6.8.14 TRIGGERIN Syntax: TRIGGERIN ENABLE | TRIGGERIN DISABLE Enables or disables external trigger input, in instruments equipped with this option. Enabling external trigger input allows you to trigger the DM24 from an external logic level supplied through its digital output port.

  • Page 77: Calibration

    Güralp DM24 MkⅢ Command line interface 6.9 Calibration 6.9.1 SINEWAVE Syntax: component freq-or-period unit SINEWAVE Instructs the DM24 to inject a sine-wave calibration signal, starting on the zero crossing. component specifies which component is to be calibrated, expressed as one of Z, N/S, E/W, or ALL.

  • Page 78: Randomcal

    Güralp DM24 MkⅢ Command line interface 6.9.3 RANDOMCAL Syntax: component RANDOMCAL Instructs the DM24 to inject a white-noise calibration signal generated by an onboard pseudo-random number generator. component specifies which component is to be calibrated: one of Z, N/S, E/W, or ALL. Some sensors use only the Z calibration loop for all three components.

  • Page 79: Amplitude

    Güralp DM24 MkⅢ Command line interface the next calibration command is SQUAREWAVE, a positive step of duration minutes will be generated, followed by a negative step of a further duration minutes. If you do not issue MINUTE, calibration signals will default to 2 minutes. Because of the way FORTH works, you can insert MINUTE commands into SQUAREWAVE, SINEWAVE or RANDOMCAL commands, for example: N/S 4 HZ 5 MINUTE SINEWAVE...

  • Page 80: Autocal

    Güralp DM24 MkⅢ Command line interface 6.9.8 -AUTOCAL Syntax: -AUTOCAL Cancels any automatic calibration setting in force. If automatic calibration is not enabled, this command has no effect. 6.10 Actions 6.10.1 LOCK Syntax: LOCK or LOCK MONITOR Locks the sensor mass(es) of the instrument connected to SENSOR A . If you issue LOCK, the command returns immediately, allowing you to close the terminal connection and follow the progress of the lock from the data streams.

  • Page 81: Masses

    Güralp DM24 MkⅢ Command line interface 6.10.4 MASSES? Syntax: MASSES? Begins reporting the current mass positions for all three components, once per second, until you press a key. Mass position information is also output on Mux channels M8, M9 and MA, if you have enabled them. Over time, and especially if the temperature changes significantly, the sensor masses may drift off centre.

  • Page 82: Lithium

    Güralp DM24 MkⅢ Command line interface RE-SYNC ON instructs the DM24 to resynchronize the real-time clock module to GPS time when a GPS fix is next obtained. RE-SYNC OFF cancels a previous RE-SYNC ON instruction, so that attaching a GPS module will no longer cause the DM24 to resynchronize.

  • Page 83: Reset-Flash

    Güralp DM24 MkⅢ Command line interface 64MB Flash File buffer : 65,536 Blocks Written 65,532 Unread 4 Free Oldest data [36,272] GURALP TESTZ1 2003 12 3 20:20:41 Read point [36,272] GURALP TESTZ1 2003 12 3 20:20:41 Latest data [36,268] GURALP TESTX2 2003 12 4 10:09:12 File Replay [36,272] GURALP TESTZ1 2003 12 3 20:20:41...

  • Page 84: Eventslist

    Güralp DM24 MkⅢ Command line interface 6.11.4 EVENTSLIST Syntax: event-specification EVENTSLIST Displays details of triggered events. The parameter event-specification can have several forms: RECENT, to display the most recent events. By default, 16 events are • displayed. You can double or halve this number by prefixing RECENT with either SHORTER or LONGER.

  • Page 85: Direct

    Güralp DM24 MkⅢ Command line interface 6.11.6 DIRECT Syntax: DIRECT Instructs the DM24 not to use Flash memory for storage. Instead, all data are transmitted directly to clients. A temporary RAM buffer allows clients to request blocks they fail to receive using the Block Recovery Protocol. 6.11.7 FILING Syntax: FILING Instructs the DM24 not to transmit blocks to clients, but to store all digitized data in...

  • Page 86: Fifo

    Güralp DM24 MkⅢ Command line interface ADAPTIVE mode is best suited for installations where the link between digitiser and client is intermittent. 6.11.11 FIFO Syntax: FIFO Instructs the DM24 to begin writing new blocks to Flash memory as for FILING, but also to transmit data to clients.

  • Page 87: Re-Use

    Güralp DM24 MkⅢ Command line interface interval the digitiser should wait for an acknowledgement message, before assuming that the block could not be transmitted. If a period of interval passes without an acknowledgement, the digitiser's behaviour then depends on the current transmission mode (see above).

  • Page 88: All-Flash

    Güralp DM24 MkⅢ Command line interface detailed description of data recording; a summary is given in section 4.5.3 on page The flash memory is used as a ring buffer. Two pointers into the memory keep track of where data were last read (the “Read Pointer”) and last written (the “Write pointer”).

  • Page 89: Stream

    Güralp DM24 MkⅢ Command line interface Instructs the DM24 to transmit all the data streams it holds next time a DOWNLOAD is issued. This command does not alter the read point or time period; you should either specify a time period or use the ALL-FLASH command in addition to this one. 6.12.4 STREAM Syntax: STREAM stream-id ( n.b.

  • Page 90: To-Time

    Güralp DM24 MkⅢ Command line interface mm is the month number (1 – 12); • dd is the day of the month (1 – 31); • hh is the hour of the day (0 – 23); and • mm is the minute of the hour (0 – 59). •...

  • Page 91: End-Download

    Güralp DM24 MkⅢ Command line interface Thus, if EVENTSLIST returns Filed @ 63,772 PLPGG SBHYZG 2006 4 16:07:50 Filed @ 63,812 PLPGG SBHYZG 2006 4 16:22:24 Filed @ 63,952 PLPGG SBHYZG 2006 5 10:14:59 Filed @ 64,005 PLPGG SBHYZG 2006 5 10:16:49 Filed @ 64,039 PLPGG SBHYEG 2006...

  • Page 92: Mbtransfer

    Güralp DM24 MkⅢ Command line interface Reading Node FFC0 . LaCie Group SA 1394-IDE Rev B2 LaCie DATA BANK drive LUN 0 Logging on @AgentCSR= 0010:00000 Capacity 39.0GB Press a key for options else 7 seconds to automatic disk backup At this point, pressing a key will cause the DM24 to display an options menu and then pause.
  • Page 93 Güralp DM24 MkⅢ Command line interface Note: The number of files stored on a disk is limited to 510. This may prevent you from using the full capacity of the drive if the value of MBTRANSFER is chosen to be particularly low. For example, a setting of 10Mb for MBTRANSFER will limit the total quantity of data stored to 5.1Gbytes, regardless of the drive capacity.

  • Page 94: Dir

    Güralp DM24 MkⅢ Command line interface 6.13.3 DIR Syntax: DIR (interactive) Lists the files already present on a FireWire disk. When you issue this command you will see the message Plug in FireWire cable and the DM24 will wait for you to plug in a compatible disk. When it detects one, it will display information about the disk and list all the files that it contains.

  • Page 95: Inside The Dm24

    Güralp DM24 MkⅢ Inside the DM24 7 Inside the DM24 7.1 State of health information The DM24 outputs diagnostic information in a status stream . This is a special GCF stream whose name ends in 00. Status streams can take two different forms, depending on the current transmission mode: In FILING mode, a short heartbeat message summarizing the current status •...
  • Page 96 Güralp DM24 MkⅢ Inside the DM24 Here, a 64 Mb Flash memory store contains 65,520 data blocks, of which none have already been downloaded. This leaves 16 blocks of free space, since each block is exactly 1Kb long, and (65,520 + 16) × 1 Kb = 65,536 Kb = 64 Mb. Latest data [392] PLPGG SBHYX2 2006...

  • Page 97: Status Blocks In Continuous Mode

    Güralp DM24 MkⅢ Inside the DM24 The system is now reporting the current offset of the internal clock from GPS time (whether slow or fast), and the current frequency error. It will now continuously adjust the internal clock for as long as the GPS is powered up. If you have chosen to save energy by enabling GPS power cycling , the DM24 will switch off the GPS once a satisfactory fix is obtained, and begin free-running on the internal clock.
  • Page 98 Güralp DM24 MkⅢ Inside the DM24 2006 1 18 14:48:00 o/s= 211 drift= 37 pwm= 8188 Auto 3D 2006 1 18 14:48:36 SOFTWARE Trigger : Trigger# 22 2006 1 18 14:49:00 o/s= 263 drift= 52 pwm= 8187 Auto 3D 2006 1 18 14:49:10 End of Trigger The messages appear in the order they are generated by the different software modules inside the digitiser.

  • Page 99: Gps And Synchronisation

    Güralp DM24 MkⅢ Inside the DM24 7.1.2.2 Trigger notifications When a trigger occurs, a message is immediately saved to the current status block. You may not see this message straight away, however, since the status block must be full before the digitiser will send it. 2006 1 18 14:48:36 SOFTWARE Trigger : Trigger# 22...

  • Page 100: Leap-Seconds

    Güralp DM24 MkⅢ Inside the DM24 7.2.2 Leap-seconds GPS time does not include leap-seconds so the firmware in the GPS receiver performs corrections to account for the difference between GPS time and UTC. This difference is the sum of all of the leap-seconds which have occurred since the GPS epoch (January 6 , 1980) and, at the time of writing, UTC leads GPS time by 17 seconds.

  • Page 101: Multiple Re-Synchronisation Events

    Güralp DM24 MkⅢ Inside the DM24 zero. (Because GPS time does not recognise leap-seconds, the "roll-over" from week 1023 to week zero actually took place at the end of 23:59:47 UTC on August the 21 Manufacturers of GPS receivers must each choose a way to determine the correct date from the GPS Week Number.
  • Page 102 Güralp DM24 MkⅢ Inside the DM24 followed by the difference between the software clock's time and GPS time. A minute later, if the new GPS time has been stable and consistent over that minute, the digitiser will step-change its clock - a resynchronisation. If the same thing happens again, the digitiser is even more sceptical and waits two minutes before reacting, again incrementing the resync counter.

  • Page 103: Updating Firmware

    Güralp DM24 MkⅢ Inside the DM24 recognised by constant extreme values of the pwm parameter as reported in the status stream. A physical repair of the DM24 is required in this case. Some Trimble Lassen GPS receivers would announce a time which was •...
  • Page 104 Güralp DM24 MkⅢ Inside the DM24 A terminal window opens, presenting you with the command line of the digitiser: If you are using a different emulator, open a window as normal with the appropriate Baud rate. The communications settings should be 8-N-1 with no flow control. Check that there is two-way communication with the digitiser by pressing Enter.
  • Page 105 Güralp DM24 MkⅢ Inside the DM24 The DM24 has three firmware components, which can be updated separately: the system program, the DSP code and the boot loader. Firmware releases are available on the Güralp Systems website (Select "Firmware" from the "Support" menu). If a release updates more than one component, you must update the boot loader first, followed by the system program and, finally, the DSP code.

  • Page 106: Setting Up External Triggering

    Güralp DM24 MkⅢ Inside the DM24 7.3.2.2 Loading a new system program To update the system firmware, press at the maintenance menu. The digitiser will display Update System program The digitiser will then request a transfer using the Xmodem protocol, as described above.

  • Page 107: Overview

    Güralp DM24 MkⅢ Inside the DM24 7.4.1 Overview The digitiser or digital instrument has two internal components related to triggering. The trigger generator runs the triggering algorithm and determines whether a • trigger has occurred. If external trigger output has been enabled, the trigger generator also operates a relay which connects the two Trigger Out pins of the DATA OUT port.

  • Page 108: Triggering Your Own Equipment

    Güralp DM24 MkⅢ Inside the DM24 7.4.2 Triggering your own equipment If your equipment can trigger from 24 V DC, the simplest arrangement is to use the voltage across the sensor's power supply as a trigger. Connect the ground pin A to your equipment's trigger return line. If your •...

  • Page 109: Using An External Trigger Source

    Güralp DM24 MkⅢ Inside the DM24 Connect the remaining pins as normal. • If your equipment needs a different voltage, you will need to provide a separate voltage source for the triggering system. Be careful not to connect two power supplies together.

  • Page 110: Triggering Several Güralp Instruments Simultaneously

    Güralp DM24 MkⅢ Inside the DM24 7.4.4 Triggering several Güralp instruments simultaneously A common use of the external triggering feature is to ensure that all instruments in an array trigger at the same time. This can be achieved with the wiring layout below. With this arrangement, any instrument can generate a trigger, which will be passed on to all the instruments in the array.
  • Page 111 Güralp DM24 MkⅢ Inside the DM24 In the case where a single power supply is used to power all of the equipment, this is not an issue and pin E should be connected directly to pin B on all units. Pin B should then also be connected to the power supply's positive terminal.

  • Page 112: Technical Details

    Güralp DM24 MkⅢ Inside the DM24 7.5 Technical details Internally, DM24 digitisers are structured as shown in the following diagram, where each box represents a separate internal subsystem. The system is designed around a low power, high performance ARM microprocessor. This is a 32-bit processor with a large address space for data storage and manipulation.
  • Page 113 Güralp DM24 MkⅢ Inside the DM24 from the ARM processor. The DSP can control all 5 ADCs and process the data in real time. An important feature of the system design is its ability to synchronise the sampling of the analogue to digital converter to an external time reference. This way, data samples are accurately time stamped at source.

  • Page 114: Güralp Compressed Format

    Güralp DM24 MkⅢ Güralp Compressed Format 8 Güralp Compressed Format Güralp Systems sensors and data modules use Güralp Compressed Format (GCF) to share seismic data. The format can be used for data storage or transmission over a serial link or TCP/UDP network. This section describes the specification of GCF format.
  • Page 115 Güralp DM24 MkⅢ Güralp Compressed Format Stream ID : a unique 6-character label identifying the device, component and sample rate: Device serial number Component O/P tap The 6-character label is encoded in 4 bytes as a base 36 number, in the same manner as the System ID , above.

  • Page 116: The Gcf Body

    Güralp DM24 MkⅢ Güralp Compressed Format compression algorithm changes the compression format, blocks may appear which are not filled to the maximum capacity. The rest of the block contains the data fields. 8.1.2 The GCF body The body of a GCF block contains the absolute value of the first sample, a 32-bit signed integer referred to as the •...

  • Page 117: Initiating A Connection

    Güralp DM24 MkⅢ Güralp Compressed Format A GCF server is expected to understand control messages, and to respond with data as appropriate. This allows clients to start and stop data transfer and to request that any missing blocks be re-transmitted. 8.2.1 Initiating a connection The default behaviour of a GCF server is to listen for UDP packets containing GCF commands.

  • Page 118: Recovering Missing Data

    Güralp DM24 MkⅢ Güralp Compressed Format 8.2.2.2 Version 40 data packets 1024 octets – The GCF block. 1 octet – The version number (decimal 40) 1 octet – A code for the byte order, as above 2 octets – The sequence number, in the byte order specified 1 octet –...

  • Page 119: The Transport Layer

    Güralp DM24 MkⅢ Güralp Compressed Format 8.3.1 The transport layer The transmission header consists of 4 bytes: Block sequence Block size Block size ASCII G (0x47) number (MSB) (LSB) Block sequence number : An unsigned integer, which increments by 1 after each block, wrapping round to 0 from 255.
  • Page 120 Güralp DM24 MkⅢ Güralp Compressed Format Stream ID should match the 4-byte stream ID of the last received block. Each system is able to identify its own ACK or NACK by matching this ID. 2-byte systems only match the least significant byte and ignore the rest. For a NACK message, Block number specifies which block number to rewind to.

  • Page 121: Connector Pin-Outs

    Güralp DM24 MkⅢ Connector pin-outs 9 Connector pin-outs 9.1 SENSOR A and B ports These are standard 26-pin military-specification plugs, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-16-26P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-16-26S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 122: Auxiliary Port

    Güralp DM24 MkⅢ Connector pin-outs 9.2 AUXILIARY port This is a standard 19-pin military-specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-14-19P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-14-19S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 123: Gps Port

    Güralp DM24 MkⅢ Connector pin-outs 9.3 GPS Port This is a standard 10-pin military-specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-12-10P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-12-10S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 124: Data In Port

    Güralp DM24 MkⅢ Connector pin-outs 9.4 DATA IN port This is a standard 6-pin military-specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-10-06P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-10-06S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 125: Firewire Port

    Güralp DM24 MkⅢ Connector pin-outs 9.5 FIREWIRE port When fitted, this is a standard 6-pin military- specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-10-06P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-10-06S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 126: Usb Port

    Güralp DM24 MkⅢ Connector pin-outs 9.6 USB port When fitted, this is a standard 6-pin military- specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-10-06P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-10-06S and are available from Amphenol, ITT Cannon and other manufacturers.

  • Page 127: Data Out Port

    Güralp DM24 MkⅢ Connector pin-outs 9.7 DATA OUT port This is a standard 10-pin military-specification plug, conforming to MIL-DTL-26482 (formerly MIL-C-26482). A typical part-number is 02E-12-10P although the initial “02E” varies with manufacturer. Suitable mating connectors have part-numbers like ***-12-10S and are available from Amphenol, ITT Cannon and other manufacturers.
  • Page 128 Güralp DM24 MkⅢ Digitiser specifications 10 Digitiser specifications Seismic channels Number 4 – 8 Format 32 bit Differential with transient Inputs protection; ±10 V input range Input impedance 1 MΩ, 10 nF Common mode 110 dB at 10 Hz rejection ratio Mux channels Number and Format Eight 24-bit channels...
  • Page 129 Güralp DM24 MkⅢ Digitiser specifications Absolute accuracy 0.5% standard (0.1% optional) -order, single-bit, low-pass noise Type shaper Clock –7 –8 8 × 10 standard (5 × 10 oven- Oscillator controlled optional) External receiver GPS or GLONASS: RS232 and PPS interface External receiver <50 µs synchronisation...
  • Page 130 Güralp DM24 MkⅢ Revision history 11 Revision history 16/12/21 Changed description of SET-ID to require adding a trailing comma to work-around RT28026. 1/05/19 Separated timing-related commands from general configuration commands and added a discussion of GPS issues. Added getWNROpivot, setWNROpivot and GPS-TYPE 4 commands. Changed transmission mode graphics and added a summary.

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